Scissors joint and blade tension means



May 10, 1949. D. c. FEATHER 2,469,373

SCISSORS JOINT AND BLADE TENSION MEANS Filed Jan. 29, 1945 6 .8 J0 I6 INVENTOR. DON IVAN C FEATHER ATTORNEY Patented May 10, 1949 MEANS SCISSORS JOINT ANDBLADE TENSION 'Donivan-C. Feather, Portland, 0reg., assignor of one-third to James B. Pfouts, Bortland, Oreg.

ApplicationJanuary 29, 1945, Serial No. 575,046

6 Claims. 1

This invention relates to scissors, shears and so forth. The primary object of the invention is to provide an automatic blade tensioning or adjustment device embodied in the'pivot bolt of the shears.

A further object of the-invention is to provide a tensioning device that will press the blades together with a minimum of pressure depending upon the toughness of the material being cut, as for instance in the cutting of thin light material it is not desirable to have a heavy pressure between the blades, but fonthe cutting of thick tough material it is desirable to be able to apply a greater leverage or tension in bringing the blades together. With my invention this is automatically accomplished, which will be more fully described and illustrated later in the specification.

These and other incidentalobjects will be apparent in the drawings, specifications and claims.

Referring to the drawings:

Figure 1 ,is a conventional type,of scissors having my new and improved tensioning device embodied therein.

Figure 2 is a cross section of the scissors, taken on line 2-2 of Figure 1, looking in the direction indicated.

Figure 3 is the same as Figure 2, except where a greater leverage is being applied in bringing together the blades.

Figure 4 is another preferred form of tensioning device.

Figure 5 is an additional feature added to that shown in Figure 4.

In the drawings:

The conventional scissor is indicated at I, having the customary blades 2 and 3 pivotally connected together by the bolt 4. The bolt 4 in this instance embodies my invention, which consists of having a shoulder 5 and a head 6 formed thereon at one of its ends. The bolt passes through the hole 8 of the blade 2, which is slightly larger than the bolt, the reason for which will be more fully described later. An enlarged hole I is formed within the blade 3 and receives the shoulder 5 therein, having a clearance 9 surrounding the shoulder The bolt and the blades are held in an assembled position by burr H1, or it may have a nut threaded thereon against the removable cap or retainer l, which is fitted to the outer end of the bolt l. Within the cap II is a lock washer 12, which supplies an initial pressure between the head 5 of the bolt and the cap ll against the blades 2 and 3, maintaining the proper tension between the blades for cutting thin or ordinary material.

Referring to Figure 3, I illustrate my device where a thick heavy-material is being cut, as pressure is applied to the scissor handles the blades 2 and i offset one past another as illustrated by the arrows, compressing the washer I2 and creating a leveragebetween the head of the bolt 6 and the washer as illustrated in the drawings, the shoulder 5 contactingthe periphery of the hole 1 of the blade 3 at 1-3 exerting'pressure diagonally opposite this point between the Washer l2 and the sideoi the-blade 2 at I l. 'The greater the pressure required to the ofiset movement of the blades depending upon the toughness of the material to be cut, will determine the pressure exerted at points is and M, bringing the blades together to ofiset thespreading action of the cut. The pressure at points l3 and I4 is obtained by the clearances B and 9 permitting the bolt 4 to assume the angleor position shown in Figure 3, when the blades are offset-inthe cutting action. From the above description it can be readily understood that I have provided a suitable blade tension within the washer l2 for ordinary cutting, saving wear and tear on the shears and fatigue to the operator, but when extra heavy work is to be performed I have provided a means of applying the extra tension for maintaining the blades in proper working relation with each other by allowing the bolt 4 to bring the blades tightly together as illustrated.

Referring to Figure 4, I have illustrated a modified form of construction, wherein the pivot bolt I5 is slidably mounted within the scissor blades 15 and N. This bolt fits snugly within the hole of the blade I6, but is movable longi tudinally therein, the blade ll being formed with a relatively enlarged hole 20 through which the bolt passes. A sleeve l8, having one of its ends i5 contacting the surface of the blade H5, at the inner end of the hole 2B of the blade l1, and its opposite end having a flange 2i contacting the inner rim 22 of the head of the bolt [5 maintaining the blades and sleeve in alignment. When pressure is applied to the handles of the shears, the blade ll will tend to offset, tilting the sleeve as illustrated, causing the end 19 of the sleeve iii to contact the wall of the hole 20 at one point, as shown in Fig. 4, and compel a tilting movement of the sleeve H3 in the hole 20. This tilting movement of the sleeve I8 forces the flange 2| to engage the outer surface of the blade I! at 23 and the inner face of the head of the bolt I5 at 24, providing a leverage between the points 24 and 3 23, forcing the blades together, first against the spring washer 30, compressing the same for light cutting, then applying the leverage between the points 24 and 23 for heavy cutting as heretofore described in Figures 2 and 3.

Figure 5 illustrates a modification of Figure 4, wherein the spring washer 25 maintains a slight initial pressure within the head of the bolt IS, the bolt it being threaded into the blade l6 instead of having a sliding fit.

I do not wish to be limited to the exact struc ture as illustrated, as other mechanical modifications may be employed still carrying out the spirit of my invention.

What is claimed as new is:

1. Means for automatically increasing the tension on the blades of scissors or the like, including a pivot uniting the blades, the blades being formed with pivot receiving openings of a size to permit relative tilting of the pivot, an independent tensioning element responsive to such pivot tilting, and means for tilting the pivot and tensioning the element to increase the pressure on the blades under increasing resistance in the operation of the blades.

2. Means for automatically increasing the tension on the blades of scissors or the like in accordance with the resistance of the blades in use, comprising a pivot for connecting the blades, the blades being formed with pivot receiving openings at least one of which is of a size to permit relative tilting of the pivot, means for tilting the pivot under pressure on the blades, and a spring washer on the pivot to be compressed under the tilting of the pivot to increase the pressure on the blades.

3. Means for automatically increasing the tension on the blades of a scissors or the like in accordance with the resistance of the blades in use, comprising a pivot for connecting the blades, the

blades having openings for receiving the pivot at least one such opening being of greater diameter than that of the pivot, an element forming part of the pivot and cooperating with the relatively enlarged opening under excess strain to tilt the pivot, said element under tilting acting to exert pressure on one blade toward the other, and a spring washer on the pivot to be placed under increased tension relative to normal in the tilting of the pivot.

4. A means for automatically increasing the tension on the blades of a scissors or the like in accordance with the resistance of the blades in use, comprising a pivot for uniting the blades of the scissors, the blades being formed with pivotreceiving openings, the opening in one blade being enlarged and the pivot having a head beyond one blade, a spring washer encircling the pivot beyond the other blade, and an element on the pivot and located in the enlarged pivot opening and having a part to cooperate with the wall of the enlarged blade opening to tilt the element under excess strain on the blades and a part to bear on the outer surface of a blade to force such blade in a direction to compress the spring washer under greater than normal strain on the blades.

5. A construction as defined in claim 2, wherein the pivot includes a pin and a sleeve encircling said pin and movable by one blade under pressure on the blades in use to increase the tension of the tensioning element.

6. A construction as defined in claim 2, wherein the pivot is provided with a flanged element to overlie one blade, and said spring washer is seated within said element.

DONIVAN C. FEATHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 842,650 Greenfield Jan. 29, 1907 844,903 I Wilkins Feb. 19, 1907 1,886,273 Thomson Nov. 1, 1932 

